Cancer is a deadly disease where your own cells attack your body,
destroying the body from the inside, leading to severe sickness and
Cancer can kill a person in
months or years.
A tumour is a mass of cells that continue to divide with no function in
The very first cell to start a tumour is created by a DNA mutation caused
by a carcinogen. The mutated cell begins dividing uncontrollably.
Normally the immune system can kill cancer cells by inducing
a) apoptosis – programmed cell death
b) necrosis – cell injury that results in premature death of cell, often
linked to inflammation of surrounding tissues
Apoptosis can occur for “normal” cells when it is time for them to die. It
can also occur as “cell suicide” if they are infected with a virus or
have damaged DNA.
Metastasis – spreading
around the body, invading
other organs and
impairing their function.
Malignant – an aggressive
cancer that metastasizes,
resulting in sickness and
Benign – a tumor that is not
A person with skin cancer may later get the cancer in their lungs
because the skin cancer may have been malignant. That means
the cancer has metastasized from the skin to the lungs.
Types of Cancer
Carcinoma: Cancers derived from epithelial cells; includes the most common
cancers (especially of old age), and nearly all developing in
the breast, prostate, lung, pancreas, and colon.
Sarcoma: Cancers arising from connective
tissue (i.e. bone, cartilage, fat, nerve), each of which develop from cells
originating outside the bone marrow.
Lymphoma and leukemia: Cancers arising from blood-forming cells that leave
the marrow and tend to mature in the lymph nodes and blood. Leukemia is the
most common type of cancer in children accounting for about 30%.
Germ cell tumor: Cancers derived from pluripotent cells, most often
presenting in the testicle (seminoma) or the ovary (dysgerminoma).
Blastoma: Cancers derived from immature "precursor" cells or embryonic
Causes of Cancer
Cancer starts with a mutation in the DNA.
Mutation – A change to the DNA sequence.
Not all mutations are harmful. Some mutations do not affect an
organism, while some cause health problems like cancer.
Causes of Cancer
A carcinogen is a factor in the environment that can cause cancer.
Three known carcinogens are tobacco smoke, x-rays, and
environmental pollution. Other carcinogens are UV radiation
(sunlight or tanning beds), viruses, organic solvents, and certain
chemicals in plastics.